The number of power demanding devices that are to be charged with a large amount of electricity, especially mobile power demanding devices such as electric vehicles, is increasing. These power demanding devices sometimes require the power demanding devices to be supplied with power from where the owners of the power demanding devices do not own or reside. For this reason, for example, power feeders such as electrical outlets, multi-taps and electric vehicle chargers with user authentication functions, which can receive power in a place where the owner of an electric vehicle does not own or reside, for example, in an apartment ground parking lot, have been developed. However, components for user authentication of such a power feeder consume power (standby power) at the time of standby operation. Further, the existing power feeder may have inconsistency between a person who pays a cost for standby power (for example, a building owner/resident) and a real actual user (for example, an electric vehicle owner).